Furnace



G. J. JUDD Jan. 4, 1938.

FURNACE Filed Jan. 20, 1956 5 Sheets-Sheet l K 0W 6 z m mn G. J. JUDD Jan. 4, 1938.

FURNACE Filed Jan. 20, 1936 [flue Mar; Qgra/ Judo. 4/ WW1;

A62? always.

Jan. 4, 1938. G. .J. JUDD 2,104,227

I FURNACE Filed Jan. 20, 1936 3 Sheets-Sheet 3 I Ge/re J Jada Patented Jan. 4, 1938 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to furnaces and particularly to furnaces of the warm air type for heating buildings and the like. A primary object of the invention is to provide a structure which will secure the greatest possible transfer of heat from the combustion of the fuel employed to the currents of air employed for heating purposes and thereby secure a high degree of fuel economy.

A still further primary object of the invention is to provide a structure which may be manufactured relatively cheaply and at the same time be extremely durable and of long life. A still further primary object of the invention is to provide a structure having an unusually large heat radiating surface in comparison to the grate bar area so constructed that the various heat transfer surfaces may be readily and easily cleaned. A still further important object of the invention is to provide heat radiating conduits which will carry heated gases of combustion down below the fire box so that the columns of air passing about the conduits from bottom to top will have imparted thereto the utmost possible heat.

These and many other objects and advantages of the invention, including the novel form of construction and ease of assembly, will become ap parent to those versed in the art in the following description of one particular embodiment of the invention as illustrated by the accompanying drawings, in which- Fig. 1 is a front elevation of a furnace embodying my invention;

Fig. 2, a top plan View; Fig. 3, a detail of a damper in vertical trans- 5 verse section on the line 33 in Fig. 2;

Fig. 4, a side elevation of the furnace;

Fig. 5, a vertical transverse section 'on'the line 5-5 in Fig. 2

Fig. 6, a vertical longitudinal section on the line 6-6 in Fig. 1;

Fig. 7, a vertical transverse section on the line 1-1 in Fig. 2; and

Fig. 8, a detail in horizontal transverse section on the line 88 in Fig. '7.

Like characters of reference indicate like parts throughout the several views in the drawings.

A combustion chamber generally designated by the numeral [0 is formed to have a floor l l preferably spaced upwardly from the ground or building floor level, and front and rear ends l2 and I3 respectively. The lower portion of the chamber is generally rectangular and is somewhat narrow in proportion to its height. The upper part of the chamber is enclosed by carrying the side walls I4 and 15 respectively around toward each other to' be joined at an upper longitudinal median line so that a cross section through an upper portion of the chamber shows an arch of Gothic nature. The front and rear ends are, of course, carried up to close off the chamber between these inwardly 5 arching upper ends of the side walls.

Beginning in the forward portion of the chamber and extending rearwardly horizontally therein is a bearing member l6 secured to each of the two sides l4 and I5 and carrying a plurality of 10 grate bars I! thereacross. A bridge wall I8 extends upwardly from the floor I l and well up into the chamber to terminate in a horizontal plane, here shown as being substantially at the junctures of the upper arched ends of the side walls 15 I4 and I5 and their lower straight portions. The height of the top of this bridge wall may, of course, be varied as desired to meet different fuel requirements and the like. The wall is preferably made out of some refractory material. 20

The member 16 in addition to rockably carrying the grate bars ll, supports a refractory lining, here shown as comprising a plurality of individual members I9 extending from the front end l2 back to and in abutment with the bridge wall [8 so as 25 to protect the side walls l4 and I5 and define a fire box therebetween over the grate bars H. The front wall I2 is provided with a throat 20 extending forwardly thereof and having an outer closure, here shown as in the form of a two-part 3O door 2|. The throat 20 is provided to admit fuel to be fed therethrough onto the grate bars [1. A refractory lining 22 is provided across the for-. ward end of the fire pot to cover over the other.- Wise exposed portion of the end wall I2 across the 35 forward end of the fire pot.

As a further means of preventing the heat of combustion in the fire pot from burning through the side walls l4 and IS, the individual refractory members l9 may be provided with vertically dis- 49 posed passages 23 which discharge from the upper ends of the members l9 and have inlets registering with holes 24 through the member l6 so that normally cool air from the ash pit below the grate bars [1 may pass up through these pas- 45 sageways 23 and thereby conduct the heat upwardly and away from the side walls Hand I5 in that zone immediately around the fire box. As a means of controlling this upward flow of air around the fire box, a slide 25 is carried under the 50 member l6 and is provided with holes that may selectively be brought into register with the holes 24 or may be so shifted as to close off these holes 24. A second throat 26 extends forwardly from the front end of the chamber ill in spaced rela- 55;

tion below the upper throat 20 and is provided with an external closure, here shown as in the form of an ash pit door 2'! so that access may be had to the ash pit formed below the grate bars I! between the side walls I 4and l5 and forwardly of the bridge wall l8.

In reference to the foregoing structure, the various side and end walls and floor and throat members may be joined together in any suitable manner such as by rivets through flanges or preferably by a continuous welded joint between the abutting members. The chamber l0 may be suitably formed of sheet steel which lends itself very well to such welded joints.

The chamber I0 is provided with an outlet opening 28 in the rear wall l3 near its upper end as a discharge into the smoke pipe 29 which extends horizontally from the wall l3. This pipe 29 discharges into a damper box 30. A damper 3| is hinged so that the discharge opening of the pipe 29 may be completely closed off at will. In the form herein shown, the damper 3| is mounted to swing on a vertical shaft 32 rearwardly into the box 3|] to be along a vertical'side thereof so that in its open position it will not interfere with the normal ,fiow of gases discharging from the pipe 29 into the box 30.

The damper 3| may be automatically operated by movement of the front fuel door 2| if so desired. In doing so, the shaft 32 which carries the damper 3| is provided with suitable connections through a lever 33, Fig. 2, abell crank 34, and a longitudinally disposed shifting rod 35 extending to the front of the furnace and thence through a bell crank 36, Fig. 1, and a connecting rod 31 to an arm 38 hinged below the lower door portion 2| so that when that door portion is pulled open, the arm 38 will be forced downwardly to shift the various connections above indicated and thereby rock the damper 3| to an open position corresponding to the open door position. That is, when the front door 2| is open, the damper 3| is likewise open, so that products of combustion may escape directly from the chamber I0 through the upper opening 28 and out through the pipe 29 into the box 30.

The box 30 discharges behind the damper 3| into a transverse pipe 39 which extends in both directions from the box 39. The right hand extending portion of this pipe 39 is interconnected with the outlet pipe 4| of the right hand heat radiator, generally designated by the numeral 40. Preferably the pipe 39 extends beyond the juncture with the pipe 4| to have a clean-out door 42 on its extreme end.

The radiator 40 comprises a plurality of horizontally disposed pipes 43 disposed in substantially parallel relation under the pipe 4|, here shown as four in number. The lowermost pipe 43 is carried well down along the side M of the chamber I0, here shown as having a portion thereof below the grate bars IT. The chamber II] is provided with a plurality of radiating fins 44 extending perpendicularly from the side walls l4 and I5 and carried around over the top of the chamber to have their inner edges welded to the walls of the chamber. Four of such fins 44 are shown in the particular form. The fins are notched out to receivethe pipes 4| and 43;

fins is spaced outwardly thereby from the side wall l4 of the chamber I0. 7

The front ends of the pipes 4| and 43 in each instance open into a front vertically disposed box 46 so that travel of gases from one pipe to the other pipe may be afforded through this box 46. Preferably this box 45 is provided with a forwardly extending throat 41 of somewhat reduced cross sectional area to be enclosed on its front side by'doors 48, 49, and 50,- all carried by a suitable frame 5|, Fig; 1. These doors are provided so that they may be opened and the various pipes 4| and 43 cleaned therethrough.

The rear ends of the pipes 43 open into a box 52, the lower end of which fits over an elbow 53 leading from an opening in the lower part of the chamber |G immediately adjacent the rear wall l3 and the floor II.

In the same manner a heat radiator 54 is provided on the other side of the chamber l0 across the fins 44 in' spaced relation from the wall l5, the upper pipe 55 of which extends rearwardly to discharge into the left hand extending part of the smoke pipe 39. The lower pipes 56 of the radiator 54 open into the forward interconnecting box 51 while their rear ends open into the rear interconnecting box 58, the lower end of which receives discharging gases from the chamber l0 through the elbow 59 over the opening 69, Fig. 6, in the lower rear corner of the side wall l5 adjacent the rear wall |3 in the floor The front box 51 carries a throat portion 6| which extends forwardly to be enclosed by the front doors 62 and 63 as clean-out doors. The pipe 39 discharges by its left end into any suitable fiue.(not shown).

A casing, generally designated by the numeral 64, is provided to surround the chamber In, its fins 44 and the radiators 40 and 54 in spaced relation. This casing 64 is preferably made to be double Walled to provide better heat insulation by means of a dead air enclosure. The casing is arched by its side walls, over the upper ends of the fins 44 in spaced relation therefrom to a median line so that all of the heated air arising between the chamber l0 and around its radiators and within, the casing 64 will tend to accumulate in the uppermost portion of the casing 64 without having any corners or depressed portions of the casing interfering therewith. The hot air is released from the casing 64 by suitable openings 65 through the casing immediately adjacent to and as desired on either or both sides of the top median line. Suitable pipe attaching thimbles or flanges 66 extend-from the casing around these openings 65.

The casing is provided with means for air intake, here shown as througha pair of conduits 6'! and 68, Fig. 2, entering through the rear end of the casing 64 and partially into laterally extending portions of the casing so that the air coming from these conduits may be discharged in the casing well toward the center thereof and under theradiators 40 and 54. The casing 64 fits snugly around the throats 20 and 26 to prevent leakage of air and also about the throats 4'! and 6| so that the clean-out doors for the radiator pipes are on the outside of the casing. A throat 69 extends from the rear wall I 3 adjacent the floor and outwardly through the rear wall of the casing 54 tobe covered by a door 10. The throat 69 permits entrance into the rear part of the chamber l0 back of the wall I8 asa means of cleaning out that particular portion.

The elbows 53 and 59 are so formed that they 1 have lower floors sloping downwardly and inwardly toward the fioor ll so that fly ash and soot removed from the pipes of the radiators may drop theredown and into the rear end of the chamber 10 to be cleaned out through the throat 69.

Preferably the sides of the casing 64 are made to be removable and are accordingly built to include the panels H and 12 which extend substantially over the radiators therebehind so that upon removing the panels, without having to disturb the remainder of the casing 64, the radiators may be easily inspected and their exterior surfaces cleaned off, and the radiators removed through the openings as may be required. In order to permit the easy removal of these radiators as above indicated, they are supported by the fins 44 being notched to receive the inner sides of the pipes thereacross and tied in position by the straps 45. By removing these straps 45, and lifting the rear box lower ends oil of the respective elbows, and first sliding the radiators rearwardly slightly to disengage their forward throats, the radiators may be lifted out through their respective side casing openings. The pipes 4| and 55 extending through the rear wall of the casing 64 are each provided with a collar 13 to form a tight seal therearound, the pipes in each instance being loosely carried through the casing to facilitate installation and removal.

In operation, combustion occurs over the grate bars I! forwardly of the wall l8 and air is admitted through the lower door 21 to support the combustion. The heated gases of combustion and smoke, if solid 'fuelis employed, travel upwardly within the chamber Ill and rearwardly over the top' of the bridge wall l8 and normally downwardly therebehind since the damper 3| is normally closed across the discharge end of the pipe 29. Of course, when fuel is being added and the door 2| is open for that purpose, the

. damper 3| is also opened to permit the escape of gases and smoke directly out the pipe 29 and into the pipe 39 into the flue so as to prevent such gases and smoke coming back out through the door 2|.

As the gases travel downwardly behind the wall I 8, they may divide and fiow out through the openings in the side walls and out through the respective elbows 53 and 59 up into the rear boxes 52 and 58 and thence divide to flow horizontally through the respective radiator pipes 43 and 56 eventually escape from the forward boxes 46 and 51 through the top pipes 4| and 55 back into the smoke pipe 39 and thence to the flue. The pipes 43 and 56 may, of course, be varied in size from top to bottom increasing in that direction so as to control the distribution of flow of gases therethrough to cause gases to flow through the lowermost pipes as well as through the upper.

Since the pipes 43 and 56 are disposed across the fins 44 and in spaced relation horizontally between the casing 64 and the side walls of the chamber III, the cooler air coming in through the conduits 61 and 68 may rise vertically on both sides of each radiator, the inner column being between the radiator pipes and the chamber wall in each case so that the upwardly traveling columns are brought into contact with the heated surfaces immediately they start rising. By extending the casing 64 laterally on both sides at the lower end, room is provided for cold air intake openings so that the upwardly travelling air columns will extend to at least the central under side of the radiator. Also by reason of the fact that the fioor II is elevated to leave an opening entirely thereunder, advantage is also taken of the floor as a radiating surface. Then, as above indicated, the upwardly flowing columns of heated air are converged one toward the other into the central top portion of the casing 64 from which the heated air may escape through the openings 65 as is apparent.

Thus it is to be seen that a downdraft type of furnace is provided having an exceedingly long flame or gas travel and having an exceedingly large radiating surface in comparison to the grate bar area and this large radiating surface is achieved without increasing the outer casing dimensions beyond those of the furnace ordinarily employed with the smaller radiating surfaces.

While I have herein shown and described my invention in the one particular form, it is obvious that structural variations may be employed without departing from the spirit of the invention and I, therefore, do not desire to be limited to that precise form beyond the limitations as may be imposed by the following claims.

I claim:

1. In a furnace, a combustion chamber, a plurality of vertically disposed fins about the exterior of the chamber, a heat radiator positioned across the fins whereby air passageways are defined between the chamber and the radiator and adjacent fins and straps securing the radiator to the fins.

2. In a furnace, a combustion chamber, a plurality of vertically disposed fins about the exterior of the chamber, a heat radiator positioned across and supported by the fins whereby air passageways are defined between the chamber and the radiator and adjacent fins, straps on the outer sides of the radiators securing the radiators to the fins and a casing about the chamber and radiator spaced therefrom to leave an air passageway between the radiator and easing, said radiator being positioned along a side of the chamber to permit said first air passageways to discharge thereabove.

3. In a furnace, a central combustion chamber having a fire-pot in its forward end discharg ing into the rear portion of the chamber, a plurality of fins vertically disposed on the sides of the chamber, a heat radiator extending along each side of the chamber and spaced therefrom by said fins, a pipe leading from said rear chamber portion near its floor and discharging into the lower rear end of each of said radiators, a pipe leading from the forward upper end of each radiator rearwardly, a smoke-pipe receiving the discharge of each of said last pipes, a casing surrounding said radiators and chamber in spaced relation therefrom, said casing having at least one cold air intake opening at its lower end, each of saidradiators being supported by said fins and means securing the radiators in position thereon.

4. In a furnace, a central combustion chamber having a fire-pot in its forward end discharging into the rear portion of the chamber, a plurality of fins vertically disposed on the sides of the chamber, a heat radiator extending along each side of the chamber comprising a plurality of pipes spaced therefrom by said fins, a pipe leading from said rear chamber portion near its floor discharging into the lower rear end of each of said radiators, a pipe leading from the forward upper end of each radiator rearwardly, a smokeat its lower end discharging vertically against the centers of the radiators, each of said radiators supported by said fins and straps on these outer sides seeming the radiators in position thereon, said fins being extended across and united with the top of said chamber for the conduct of heat to and the suspension of the radiators from, and said casing being arched over the chamber by each side to meet on a top longitudinal median line, the casing having hot-air outlet openings adjacent said line, said chamber having its top formed by arching the sides over one toward the other to meet on a longitudinal median line.

5. In a furnace, a combustion chamber, fins 7 extending vertically on the outer side Walls of the chamber, a heat radiator, said fins being pipe receiving the discharge of each of said last rnovable' side members and straps retaining the radiator in position on the fins located on the sides of the radiators next to the removable sides of the casing.

6. In a furnace, a combustion chamber, a plurality of vertically disposed fins about the exterior of the chamber, aheat radiator supported by the fins andpositioned'across the fins whereby air'passageways are defined between the chamber and the radiator and'adjacent fins, straps on the far side from the chamber removably securing the radiator to thefins and a casing extending over the top and down the sides of the chamber and radiator and spaced therefrom to leave a passageway therebetween said casing being double Walled and formed with dead air spaces throughout to prevent loss of heat by radiation.

GENE J. JUDD. 

